This post-judgment garnishment case is controlled by Coursin v. Harper, 236 Ga. 729 (225 SE2d 428), as the affidavit upon which the summons of garnishment was issued was given prior to July 1, 1975. Battles v. Battles, 138 Ga. App. 841 (227 SE2d 524). This proceeding must therefore be declared "void and of no effect" (Rose, Silverman & Hunt v. Ben O'Callaghan Co., 134 Ga. App. 648 (215 SE2d 515), where we decided the issue sua sponte), and the judgment dismissing the proceeding is affirmed. "It is fundamental that a judgment of a trial court which is right will be affirmed on appeal even though the trial judge in rendering his judgment may have assigned a wrong reason therefor." Sims T.V., Inc. v. Fireman's Fund Ins. Co., 8 Ga. App. 41, 43 (131 SE2d 790).